Why are there no PWC/ Jet Skis with V-Twin Harley-Style Engines?

Discussion in 'Jet Drives' started by Chris Hall, Aug 10, 2009.

  1. Chris Hall
    Joined: May 2008
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    Chris Hall Junior Member

    I have wondered this for a while...the only thing I don't like about PWCs/ Jet Skis is the "ring-ding-ding" weedeater sound...seems like there should be enough torque with a V-Twin Harley-style engine that would produce a lot cooler rumbling exhaust tone on a jet ski.

    I understand that V-twins operate at a lot lower RPM than traditional PWC engines, but it seems like gearing could solve that problem.

    Kawasaki makes the Vulcan 1500 that sounds really good and it's water-cooled---check out this video:

    http://www.youtube.com/watch?v=5owu8yDxED4


    Also thought it would be possible to use a Chevy V-8 like they do in the Boss Hoss motorcycles to get that exhaust tone on a PWC.

    http://www.youtube.com/watch?v=gbgIpZZxSKI

    http://www.youtube.com/watch?v=VXt4wvvMIE0

    Interested in your thoughts on why no one has done it yet.
     
  2. apex1

    apex1 Guest

    Well, I guess, because most designers of such craft are mentally intact. Who would call a Boss Hoss a motorcycle? Or a Harley V twin a engine?
     
  3. Chris Hall
    Joined: May 2008
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    Chris Hall Junior Member

    It's an American thing, you wouldn't understand...:D
     
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  4. Chris Ostlind

    Chris Ostlind Previous Member

    It could be done, Chris, if one were to use a slightly breathed-on Sportster engine that was setup for watercooling. Because such a thing doesn't exist, AFAIK, you'd get further down the line with another bike engine that was setup for offroading, where weight is held down and the power curve is elevated.

    A quick search for 4 stroke engines in this category would maybe yield an answer.

    The problem, as you have probably guessed, is weight factors. While street bikes are ultimately concerned with all-up weight to some extent, their offroad brothers are totally obsessed.

    If it's that vee-twin sound you like, you may just be out of luck.

    Truth be told, I have never been impressed with Harley's engine technology, such as it is. They long ago saddled themselves with an engine that has all sorts of design issues, in order to save that sound and have made next to no attempt to join the push to engine potential outside of that really primitive technology.

    Everybody in motorcycling long ago left Harley in the dust.

    And that's my rant just a bit off topic for the day.
     
  5. Chris Hall
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    Chris Hall Junior Member

    That's why I thought the Kawasaki Vulcan engine would work fine...they have a few different sizes (900, 1500) that have the Harley sound but water-cooled and dependable. The next challenge would be to marinize it, then mate it to a jet drive...

    The more I think about it, a V8 would be pretty awesome to shoe-horn into a PWC-style craft, and I'm thinking that there are jet drives that already exist for that engine, plus the V8's have already been marinized for the last 50 years or so. I guess the next step would be to retro-fit a PWC hull that would accept it...maybe get an aluminum LS-series Vette engine to save some weight?
     
  6. Chris Ostlind

    Chris Ostlind Previous Member

    Then let's quit messing around with heavy American iron, Chris. Why go Vette, when you can get the finest go-fast engine made for its size; The Cosworth 3L F1 DFV Short Stroke. 264 lbs. with power ranging from 415 hp to 520, depending on configuration, and a redline of 9000 rpm.

    That is a much better power to weight ratio than any Vette engine that could possibly fit in a PWC.

    And that sound.

    In the end, it's all about the weight. The heavier the engine, the fewer people you can carry. Want to keep the same passenger load, then the hull has to get bigger... and so goes the spiral.

    That's why the PWC market was totally dialed into two strokes for so long, even when the manufacturers knew that they were very bad for the environment. They rev instantly, producing very quick power and they are much lighter than their four stroke brothers.
     

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  7. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    A HD Sportster engine has it's transmission and engine case as a single unit, so this engine is out. You'd have to use the big twin single or duel cam engine as they are just engines.

    All of these HD engines are first class engineering and something Richard is clearly not acquainted with, particularly the fact that the first generation "Evo" HD V twins where designed by Porsche! They don't leak, they produce globs of power and are copied by nearly every other motorcycle manufacture in the world, so there must be something to these big twins.

    Anyone unfamiliar with HD engines since the AMC days (1970's) wouldn't have a clue about their reliability, torque, etc. This coupled with you can't judge one unless you've actually spent considerable time on one. Trust me, I use to own an "outlaw" HD shop and you don't get laid riding a Honda, just because you're riding a Honda, but you will if riding a Harley.

    The Boss Hoss is a ***** of a bike to ride, but surprisingly accommodating, just don't drop it. It's a warm bike to live with and doesn't have much going for it, unless you enjoy having your nuts flapping in the breeze, when you grab a handful of throttle. If you'd like a closer relationship with a supreme being, take a Boss Hoss out for a few full throttle blasts.

    The HD big twins would make a reasonable boat motors, but why bother, except for the novelty of it. I haven't seen one yet, but I'm quite sure someone has shoe horned a small block Chevy into a big PWC by now. This is the first engine to get grafted into anything (they work good on motorcycles), so you can be they're out there. Weight would be an issue as a full up small block, with a transmission is about 900 pounds. But given you can have upwards of several hundred reliable HP, could be a fun ride. Hell, I use to have a 454 CID stuffed into a Opal GT, now that was a fun car and it didn't sound remotely like a Toyota.

    For what it's worth, Kawasaki has never made an engine that sounds good. Good sounding engines are universal, the V12 Packard, the Rolls/Merlin 12 used in the P-51, small block Chevy, big block Chevy, the flat head Ford, HD air cooled V twins and several others all would be considered internationally acclaimed good sounding engines. The Japanese haven't figured out how to make a decent sounding exhaust yet. I think it's an inner ear problem.

    Chris, light engines in light boats work well, but you can wind up a small engine all you want in a heavy boat and just wish you had some real torque, instead of multiplication. Of course if you toss an aluminum 2,000 HP big block Chevy cranking 2,500 ft. lbs. of torque, in that heavy boat then you've got a fire breather.

    In the end you have to pay the piper. If you can't afford it, you go little, but many pistons. If you can afford it, you increase displacement and reciprocating mass.
     
  8. apex1

    apex1 Guest

    Paul
    >>>something Richard is clearly not acquainted with<<<

    thats true, but that:

    >>>first generation "Evo" HD V twins where designed by Porsche!<<<

    I know.

    And a Boss Hoss is´nt a Motorbike, it´s a "Two wheeler"

    this is a bike! A real one....

    [​IMG]

    Regards
    Richard
     
  9. Chris Ostlind

    Chris Ostlind Previous Member

    PAR,

    The EVO may have been "designed" by Porsche, but it was done on a strictly controlled set of parameters as delivered by Harley. The result was equivalent to Hall Of Famer, Sandy Koufax, being called in to pitch for a sandlot team. Dude can bring a golden arm to the game, but he’s still got to pitch from the same crappy mound. I wouldn't be of the opinion that a world class engineering company, such as Porsche, who had already produced ultralight and seriously powerful, dual overhead cam engines capable of winning at LeMans, would really specify a powerplant like the EVO.

    Back in the 70's, I raced 350 production on what was essentially, a street legal Yamaha twin. Not only did I get plenty of offers for the soft stuff, but I regularly ate Harley's for lunch. Stop light to stop light, canyon blasting, never once punched-out by the heavy, slow revving, teeth rattling "potency" of any Harley that was street legal in SoCal. I'm not sure, but I think it had to do with the power to weight, the instantaneous power, typical rider quickness on a more responsive machine and most of all... the satisfaction of giving a smile to His Badness when he finally did roll-up to the next light.

    Back in that day, Harley was fielding a gang of very good riders in the AMA Grand National events around the country. One of those events was held during the annual Daytona Speed Week where all the competitors brought their rides to jam around the famous road race circuit. The Harley Boys were just peachy as hell if Kenny Roberts brought his Yam four stroke twin, but the day the big yellow truck arrived carrying serious, 350 two stroke GP equipment, they kinda got pushed to the middle of the pack. All while they had the same view of Kenny Robert’s butt, as the boys in SoCal did of mine.

    Two years later, Yamaha rolled-out their 750 GP road racer and it was all she wrote for Harley on the asphalt. Geez, Kenny Roberts even rode a modified 750 GP bike in the famous Sacramento Mile dirt track event and "somehow" managed to dust the Harley team by a full lap. What did the Harley team do after that.... they whined to the AMA that it wasn't fair and threatened to take their team off the track. I love that bit of submissiveness in the face of a better-engineered and performing product; "I'm going to take my ball and go home". They never said anything even remotely like that when they were winning their share of races, so where'd the balls go?

    That singular event shall be the eternal lament of the Harley dirt track team... The day they packed up like sissy's when a simple rice burner shut their puffed-up, macho image down.

    No offense, PAR, but Harley chose their path of engineering indignance and in so doing, they cast the die that will perpetually limit their ability to engineer a truly competitive product. The answer is not in the application of ever-bigger jugs, carbs etc. It resides in a better engineered, lighter moving mass powerplant that revs instantly. An engine that churns out F1 quality power per cc in a more compact size that allows superior chassis geometry.

    There's a reason why you do not see Harley twins out on the track (even in this modern day) when they've had plenty of time to create a respectably competitive powerplant. Suzuki, BMW, Yamaha, Honda, Ducati... all of them, have constantly moved the bar higher while Harley has lowered its expectations into a pure novelty machine.

    The boys from Wisconsin have choked their own chicken and settled for their wannabe niche marketing angle. An angle, I hate to say, that has gotten seriously thrashed in this current world economy. The company just shutdown another 1000 plus workers with no near term anticipation of firing it back up. The days where thousands of pimped-out attorneys, sporting leathers right off the pages of a glossy Harley Accessory Catalog, hauling their rides to Sturgis in a trailer behind their Escalade are gonna, hopefully, pass before us like a purists bad dream. Might as well spray on a coat of Rhinoliner to the streets of Sturgis; It has gotten that pedestrian.

    I went there in '73 to take in the spectacle and revisited in '94 and found the "atmosphere" seriously poisoned by the elitist gloss. WTF is a real biker rally when you see moms and kiddies strolling the streets of the town with cotton freaking candy and tourist trinkets in their hands? And Harley happily bumps along, sweeping-up large profits from the sales of more Middle Class crapola. What the heck has happened to that company, anyway?
     
  10. Chris Hall
    Joined: May 2008
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    Chris Hall Junior Member

    I like that quote..."inner ear problem"!

    I've been searching on the 'net for anyone that has put a small-block in a PWC and can't find anything.

    I found that the weight of the LS series aluminum small block is 430 lbs. without a transmission, and will produce quite a bit of horsepower and torque (and music). Standard horsepower from the earliest LS1 is 350 hp/365 tq and the bad LS7 stock is 505 hp/ 470 tq. When modded, these are crazy fast engines; 700-900 horsepower is not uncommon. I haven't heard of the Cosworth before, forgive my ignorance, but I can't imagine them being reasonably priced, or a person having the ability to get replacement parts quickly and inexpensively.

    http://ls1tech.com/forums/new-ls1-owners-newbie-tech/242392-ls1-weight.html

    What's also cool about the Vette LS1 is the dry-sump oil system available for the LS1-LS6 (and standard on the LS7) that keeps oil pumping to the engine when exerting lateral g's.
     
  11. mark775

    mark775 Guest

    I like v-twins, as well, but a different flavor. Aprilia, Ducati, Highland (Just happens to be alphabetical. Hadn't thought of it, but that Highland from Sweden (made in China, tho) would be sold independent of the bike and is a torque monster.
    Look into four-stroke snow machines for what might work in a wet bike. The mountains crowd has been nearly shut down by their noise for decades and some went this route.
     
  12. TollyWally
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    TollyWally Senior Member

    LOL Chris,
    Would that possibly be the infamous RD 350 Yamaha? My buddy had one of those, we used to switch bikes and terrorize the neighborhood. Lots of stories, good times. It was more bike than I could safely handle. I thought of it as the most dangerous motorcycle in the world. In a good way :)
     
  13. Chris Ostlind

    Chris Ostlind Previous Member

    Yep, that's the bugger. Rode it to college everyday when it wasn't raining.
     
  14. apex1

    apex1 Guest

    Was a nice beast, but the first Mach III, 500ccm 3cyl. Kawa, was twice the danger, no breaks, no frame, no nothing worth talking just ENGINEEEEE and consumption like a 80 tonnes tank at full throttle. 1969, yeah, we grow older, my Hayabusa is a pussycat compared with that Mach III beast.
     

  15. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    A small block Chevy can produce over 2,000 hp, though engine life is rated in minutes. A big block doubles this with the same side bar. Fairly reliable versions of these engines can be had at half those HP figures, though you'll be at the parts store frequently.

    Unless you've twisted the grip on a Boss Hoss, you can't appreciate what they are. Most folks don't understand, unless they're like me and willing to stuff a big block Chevy in one of these just for fun.
    [​IMG]

    Tossing 500+ HP in a 1,500 pound car is entertaining, not practical. Riding a raked, big twin with a suicide shift and no front brake is entertaining not practical.

    Look there's those that buy a big BMW, slap some bags on it and head out, because "they like to ride". Then there's those that think that's not riding and would prefer to have their feet up, their backs reclined and enjoy the idea of bugs dieing terrible deaths on their teeth or forehead.
     
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